Security guards employed by Indian-owned RK Viet Nam on September 27 attacked a group of protesters at the company’s marble quarry in Lam Thuong commune, Yen Bai province, according to a statement by Amnesty International.

During the fracas, in which the guards used guns, batons and electric cattle prods, 11 of the several hundred protesters were injured, the statement said.

The protesters were mainly of the Tay indigenous community living in the villages near the quarry. They had gathered that day to protest pollution related to the operation of the quarry, which they say has poisoned their only source of clean water and killed large numbers of fish and poultry, the report said.

In addition, the mountain on which the quarry is situated is considered a spiritual guardian of the local communities by the Tay people.

Amnesty International said video and photo evidence taken by people on the scene during the attack was provided to them and local rights groups. One video shows that rapid-response police were there while the attack as going on, but did nothing to intervene.

The report also said that following the attack, local authorities ordered the company to temporarily cease operations to smooth things over with the community. Local activists told the NGO that police came to their homes and demanded they delete social media posts about the event.

On October 4 the local district president Bui Ban Thinh ordered that the police track down information about those who posted about the attack on Facebook.

Several people who were on the scene spoke to RFA’s Vietnamese service and confirmed the veracity of these reports about the incident, but declined further comment, fearing reprisals.